Fuel injection nozzle



April 27, 1943. H, FISCHLMAYR 1 9 'FUEL INJECTION NOZZLE v Filed July 13, 1940 2 Sheets-Sheet l jn venlar All6rne ys.

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April 27, 1943.

FUEL INJECTION NOZZLE Filed .July 13, 1940 N. F/M

H. FlscHLMAvR 2,317,749

2 Sheets-Sheet 2 Patented Apr. 27, 1943' 2,317,749 FUEL INJECTION NOZZLE Hans Fischlmayr, Grafelfing, near Munieh,.Germany, vested in the Alien Property Custodian Application July 13, 1940, Serial. No. 345,362 In Germany March 16, 1939 8 Claims.

This invention relates to fuel injection nozzles for internal combustion engines of the injection type, such as Diesel and semi-Diesel engines.

The use of especially developed combustion spaces for internal combustion engines makes possible an exceptional saving of fuelin cases where perfect combustion is attained. Perfect combustion requires, however, that the fuel be introduced in the form of an injection cone with a wide angle, filled approximately uniformly with fuel, the speed of flow of the fuel being relatively low. These requirements are not met in injection nozzles heretofore known, since either the shape of the injection nozzle is unsuitable or the speed of flow is too high. I

The'object of the present invention is to create an improved and more satisfactory fuel injection nozzle, which meets the above mentioned requirements.

To these and other ends the invention resides in certain improvements and combinations .of parts, all as will be hereinafter more fully described, the novel features being pointed out in the claims at the end of the specification.

In the drawings:

Fig. 1 is a cross section through the mouth of From the space 26, the direction of flow of the" an injection nozzle according to one embodiment I of the invention, and

Figs. 2 to 9, inclusive, are similar views each illustrating a different embodiment of the invention.

The same reference numerals'throughout the several views indicate the same parts.-

It is found that very favorable results are attained with the use of a nozzle so designed and constructed that the injected fuel is conducted from a place of high pressure, under considerable change in its direction of flow, to an approximately disk-shaped space, and then flows inwardly toward the center of this disk-shaped space, preferably from all directions, to a discharge opening located at or near the center of the disk-shaped space, the space being of such size and location that the resistance to flow at,

the inner annular edge of the disk-shaped space is at least as great as the flow resistance through the drawings, there is provided a nozzle body In in which a valve body i2 is longitudinallymovable. This valve body i2 has a shoulder i4, and a second shoulder iii of conical shape, seating against'a corresponding conical shoulder of the body Ill and constitutin the valve.

A portion i8, preferably cylindrical, extends forwardly from the conical seat 16 and terminates in an end 20 which is located in the immediate proximity of the nozzle plate 22, preferably only a few hundredths of a millimeter therefrom, when the valve is closed.

The fuel, under pressure from the fuel injection pump, enters through the duct or passageway 24 leading to an annular space beneath the shoulder M.- The pressure of the fuel acting upwardly on the shoulder 14 lifts the valve body against the.pressure of a suitable spring (not shown) and this lifts the conical valve portion i6 oil of its seat, permitting the fuel to flow along the conical surface i6 and into the annular space 26 surrounding the cylindrical extension l8.

fuel is sharply deflected so that the fuel flows from all sides inwardly toward the center of the annular disk-likefiow space between the end surface 20 and the nozzle plate 22; Immediately after flowing through this restricted disk-like flow space, offering relatively high resistance to flow, the fuel reaches the central opening'in the nozzle plate 22, and then can expand freely through this opening into the combustion space 28, thus being practically completely atomized in a very favorable manner, through a wide angle, and a proximately uniformly, with no individually directed streams or jets of fuel.

It will be understood that when the valve is opened or lifted by pressure of the fuel on the shoulder iii, the opening movement is very slight. so that theend 20 of the valve member still remains, even when opened, in close proximity to the upper surface of the nozzle plate 22, and the a facturing difliculties are involved, and also the thin edges are subjected to undesirable wear phenomena, especially if the fuel is not suflicientlycleaned or purified. It is preferable to J make. the injection opening of appreciable length, in order to avoid the sharp edges, and it may be made as indicated at 30 in Fig. 2, the other parts in this figure being the same as in Fig. 1. For best results it is important, however, that the axial length of the orifice must not exceed half of the diameter of the orifice.

It is not absolutely necessary that the annular disk-like flow space leading to the discharge orifice be in the form of a flat disk, and there is no objection to making it in the form of a.

orifice of substantial length (but not over half its diameter) as shown in dot-dash lines at in Fig. 3.

of the valve, just as in the case of Fig. 4. Also, whether the-lower end of the valve member be fiat'or whether it be conical, in either event the accompanying injection orifice can be developed in any of the ways described in connection with Figs. 5 to '7.

In Fig. 9 there is illustrated still another form of the invention, embodying the valve chamber and valve member of the same form shown in Fig. 4, in connection with an injection orifice of the same form shown in Fig. 2. The same reference numerals used for these parts in Figs. 4

and 2, respectively, have been used in Fig. 9.

There is shown in Fig. 4 a different embodiment of the invention, in which, instead of having the valve constituted by the conical shoulder IS on the body l2, this shoulder remains always substantially separated from the corresponding conical shoulder ll of the body l0, and the valve itself is constituted by the end 20 of the cylin-' 'drical extension l8 actually seating on the upthe pressure of the spring (not shown) thus While certain embodiments of the invention have been disclosed, it is to be understood that the inventive idea may be carried out in a number of ways. This application is therefore not to be limited to the precise details described, but is intended to cover all variations and modifications thereof falling within the scope of the appended claims.

I claim:

1. An injection nozzle and valve for internal combustion engines comprising a chamber having a substantially cylindrical portion and an end wall having an injection orifice extending therethrough, said orifice having an axial length of lar flow passage between said portion of said the seat 2| and opening the valve.

Whenthe valve member and said portion of said chamber,

- said valve member having an end surface lying closely adjacent said end wall of said chamber in overlapping relation to said orifice, said end surface of said valve member being sufllciently valve is opened, the flow takes place, through the annular disk-like space between the end 2| and the surface 2|, in the same manner as already described.

when the injection orifice is made of substantial length to eliminate the sharp or thin edges, it is not necessary to make this orifice of strictly cylindrical shape as shown in Fig. 2 of the drawings, but it is frequently advantageous to make it as a somewhat conical bore, expanding in the direction of flow, as shown at II in preferably both the outer'an'd inner' edges are.

rounded, as seen in this figure.

'Ihese arrangements in Figs. 5 to 7 have the advantage that any directional effect of injection is eliminated to a greater extent, as compared with the arrangement shown in Fla. 2.

In Fig. 8 there is illustrated a modification of the dished or'conical arrangement described in sists in slightly truncating the conical portion 32 by substituting a fiat surface 28 for the point of the cone. This has the advantage that excessive heat stresses on the point of the cone are avoided. It may also be noted from Fig. 8 that when the valve member is made with a conical or truncated conical end as in Figs. 3 and 8, the

connection with Fig. 3. This modification conlower end of the valve member can itself seat against the plate 22 to form the sealing portion close to said end wall of said chamber when said valve member'is in its open position so that the resistance to fluid flow toward said orifice in the space between said end surface and said end wall immediately around said orifice is at least as great as the resistance to flow outwardly through said orifice.

2. A construction as described in claim 1, in which said end surface of said valve member adjacent said end wall is substantially fiat and in which the surface of said end wall cooperating with-said end surface to form said flow space is also substantially flat.

3. A'construction as described in claim 1, in which said end surface of said valve member adjacent said end wall is at least partially conical and in which the surface of said end wall cooperating with said end surface to form said flow space is also substantially conical.

4. A construction as described in claim 1, in which said end surface of said valve member adjacent said end wall is of truncated conical shape with a flattened end and in which the surface of'said end wall cooperating with said end surface of said valve member to form said flow space is substantially conical.

5. A construction as described in claim 1, in

which said iniection orifice is of material axial length and in which said axial length is not more than half the diameter of said orifice. 6. A construction as described in claim 1, in which said infection orifice opens into a conical section with a relatively great apex angle of more than so that injected fuel issuing from said orifice may spread immediately through a relatively wide angle.

'1. An injection nozzle and valve for internal combustion engines comprising. a chamber having a substantially cylindrical portion and an end walliha'ving an injection orifice extending therethrough, said orifice having an axial length of not more than half of its greatest cross sectional dimension, and a valve member including a substantially cylindrical portion movable axially within said portion of said chamber and spaced from the side walls thereof to provide an annular flow passage between said portion of said valve member and said portion of said chamher, said valve member having an end surface lying closely adjacent said end wall of said chamber in overlapping relation to said orifice, said end surface of said valve member lying against said end wall of said chamber in sealing relation thereto when said valve is closed and. moving rearwardly away from said endwall to open said valve and remaining sumciently close to said end.wall when said valve is open so that the resistance to fluid fiow toward said orifice in the space between said end surface and said end wall immediately around said orifice is at least as great as the resistance to flow outwardly through said orifice.

8. An injection nozzle and valve' for internal combustion engines comprising a chamber having a substantially cylindrical portion, a rearwardly faced shoulder associated with said porspace between .Said end surface andsaid end walltion, and an end wall spaced forwardly from said shoulder andhaving an injection crifice extending therethrough, said orifice having an axial length of not more than half of. its greatest cross sectional dimension, and a valve member including a substantially cylindrical portion mov-- able axially within said portion of said chamber and spaced from the side walls thereof to provide an annular flow passagebetween said portion of said valve member and said portion of said chamber, said valve member having a forwardly faced shouideradapted to 'lie against said rearwardly faced-shoulderof said chamber in sealmember is in its open position so that the resistance to fluid flow toward said orifice in the immediately around said orifice is at least-as great as the resistance to flowoutwardly through said orifice. 

